Air vent valve



May 5, l942 L. w. n-:GsLEs-roN AIR VENT VALVE Filed April 22, 1940INVENTOR TTORNEY Patented May 5, 194

AIR VENT VALVE Lewis W. Eggleston, Davison, Mich., assignor to DetroitLubricator Company, Detroit, Mich., a corporation of MichiganApplication April 22, 1940, Serial No. 331,005

17 Claims.

My invention relates generally to valves and more particularly to airvent valves for heating systems. Y

One of the objects of my invention is to provide a new and improved airvent valve of the type adapted to vary the rate of egress of air from aheating system in accordance with the pressure in the system todetermine the rate of admission of a heating medium to a heat transferelement of the system.

Another object of my invention is to provide an air vent valve in whichthe noise formerly caused by air escaping to atmosphere is eliminated.

Another object of my invention is to provide an air vent valve havingprovisions for removing entrained moisture from the air prior to egressof the air from the valve.

Another object of my invention is to provide an air vent valve of theabove mentioned character having a new and improved arrangement of theoperating and associated parts thereof.

Another object of my invention is to provide an air vent valve havingprovisions of a simple and inexpensive character to vary the rate ofegrass of air by the valve in accordance with the pressure in a heatingsystem.

Another object of my invention is to provide an air vent valve havingnew and improved mechanism for regulating or adjusting the ventingcapacity of the valve.

The invention consists in the improved construction and combination ofparts, to be more fully described hereinafter and the novelty of whichwill be particularly pointed out and distinctly claimed.

In the accompanying drawing, to be taken as a part of thisspecification, I have fully and clearly illustrated my invention, inwhich drawing- Figure l is a top plan view of my improved air ventvalve; x

Fig. 2 is a vertical central sectional view of my valve taken along theline and in the direction of the arrows 2--2 of Fig. l;

Fig. 3 is a view of my device shown in crosssection, taken along theline and in the direction of the arrows 3-3 of Fig. 2;

Fig. 4 is a fragmentary view shown in section of my device, taken alongthe line and in the direction of the arrows 4 4 of Fig. 3;

Fig. 5 is a fragmentary View of my device shown in cross-section, takenalong the line and in the direction of the arrows 5-5 of Fig. 4;

Fig. 6 is a fragmentary view of my device shown in cross-section, takenalong the line and in the direction of the arrows 5-6 of Fig. 2;

Fig. '7 is an enlarged detail view of certain of the valve members shownin the transitory position of vtheir simultaneous engagement with theirconcentrically arranged valve seat portions;

' closes an opening in, the casing top wall 2.

Fig. 8 is a view shown in perspective of a valve member of my air ventvalve, and

Fig. 9 is a view of a modified valve member for my air vent valve.

Referring to the drawing by characters of reference my air vent valveincludes a casing I, preferably of general tubular form having a topwall 2, a continuous side wall 3 and a bottom wall Il.` The side wall 3has an annular offset surrounding portion lla formed by the telescopicunion of upper and lower side wall portions and having afunction to bedescribed. The casing I has a nipple 5 in the form of an open endedtubular tting that may be secured in and to the casing side wall 3adjacent the casing bottom wall 4. An outer end portion of the nipple 5may be threaded, as at 6, for screw-threaded connection to a steamradiator or heat transfer element of a. heating system (not shown).Extending longitudinally through the nipple 5 there is shown a Siphontube 1 for the return to the radiator of any water that may happen tofind its way into the valve casing I. An aperture 3 is preferablyprovided through the side wall of the nipple 5 for the passage of airfrom the radiator into the valve casing l, the aperture 8 preferablyopening upward into the casing, as shown.

Mounted on and rigidly secured to the casing top wall 2 there is a valveseat member or body Ill that projects into the casing through, and

Preferably the valve seat member I0 has a plate-like portion I I thatmay seat on the upper surface of the casing top wall 2 and has apassageway I 2, which is preferably a hollow cylinder having adownwardly directed open end within the casing I. The cylinder I2preferably has itslongitudinal axis extending substantially verticallyand this hollow cylinder may be defined by a tubular extension orportion I3 which may be integral with, and depend from, the plate-likeportion of the valve seat member ID. The cylinder or passageway I2 opensupwardly into a relatively small passageway I4 provided in the valveseat member I0, the passageway I4 preferably being a verticallyextending bore disposed in longitudinal axial alignment with thecylinder I2. The passageway or bore I4 opens through the upper surfaceof the plate-like portion II and at lower end there is a downwardlyfacing port and seat I6 for cooperation with a valve member I'I. Thecylinder IZ and bore I4 provide a passage- Way through the valve seatmember I0 for the escape or egress of air from the casing I. Theinternal diameter of the cylinder passageway I2 is larger than thediameter of the bore or passageway I4 and terminates in an upper endwall forming a shoulder which is preferably conical', as at I8, theshoulder providing a valve seat which tapers or converges inwardlypreferably toY the port I6 of passageway Ill. The valve member I1extends upwardly, longitudinally within the cylinder I2, and the upper.end or face of the valve is preferably rounded, as at 23.

The valve member I1 is preferably carried by and rigidly secured to thetop of a thermostatic float, designated in general by the numeral 2i,which is disposed within casing I below the valve seat member I3. shown,is a well known typehaving, al closed container 22 charged with atemperature responsive, eXpansible-contractible uid such as, for eX-ample, alcohol. Below the lower end of the theraction of thermostaticfloat 2I, however, it should be noted that when valve member 21 isseated as shown in Fig. '1 that upon the valve member I1 closing theport I6, as is also shown in Fig. '1, the pressure above and below valvemember 21 will be equalized so that the valve The thermostatic floatv2I, as.

mostatic float 2l there is a supporting member 23 therefor, preferably ascrew that is vertically, adjustably screw-threaded into a substantiallyhorizontally extending metallic strip 24 that may have its opposite endssecured in and to the casing side wall 3. The screw 23 is arranged sothat the bottom wall, as at 25, of the thermostatic float 2| seatscentrally thereof on the upper end of the screw. The bottom wall 25 ofthe container 22 is flexible and iexes downwardly on expansion of thefluid in the container. This causes the container 22 to move upwardcarrying with it the valve member I1 which moves toward and is adaptedto engage its seat I5 to prevent escape of the heating medium throughthe air vent passageway I 4.

A pressure responsive, piston type valve 21 is provided to control flowof air through the passageway i4 and is arranged for vertical movementWithin and longitudinally of the cylinder I 2. The valve member 21 ispreferably of general tubular form having its opposite ends open, andsurrounds and cooperates with the thermostatic float valve I1 and theconical seating surface I8 to control flow through the passageway I4.The valve member 21 loosely surrounds the valve member I1 so as to befreely movable relative thereto and so as to provide an annularpassageway 23 therebetween for restricted now or passage of air. Theupper end of the valve member 21 is preferably rounded, as at 29,entirely therearound providing a seating surface or face for seatingagainst the conical wall I8 of the cylinder I2. The valve member 21 hasa piston portion 33 which may be an outturned, external annular flange,preferably provided at the lower end of the valve member. portion may becylindrical in shape and the diameter thereof is slightly less than thediameter of the cylinder I2 so as to provide an annular space 3l betweenthe piston side Wall and the wall of the cylinder for restricted now orpassage. of air. lThe valve vmember 21 is carried by the valve member I1which is formed having an upwardly facing, external shoulder or seatingsurface 32 on which the valve 21 is4 adapted to seat, as shown in fulllines Fig. 2. Preferably thev Valve member 21 is arranged such that whenit is seated on the shoulder 32 andv the valve I1` is open, the pistonportion 30 of the valve member extends slightly within the cylinder I2.As. will b e. apparent from the foregoing and from the, showingv of Fig.l1, the portion 32a of surface I8 closely surrounding. port I6 serves asa -seat for valve member I1, and an annular portion 32h of surface I8,spaced from surface portion 32a, serves as al seat for valve member 21.As is pointed out hereinafter, the valve member 21 is engageable withthe outermost seat portion 32h upon occurrence of a pressuredifferential, and the valve member I1 is engageable4 with the 'innermostseat portion Y312al under the The piston member 21 will thereupon fallto its seat on shoulder 32 of the valve stem.

A plate-Hike, manually operable valve 33 is provided and seats on thetop surface of the valve' seat member I0, the valve 33 being operable`to regulate the venting capacity of the air vent valve. The manuallyoperable valve 33 is preferably pivoted on an upstanding pivot pin 34that may have one end secured in and to the valve seat member I0. Thevalve 33 overlies the discharge opening of the passageway or bore I4 andin its underside has a recess or outlet chamber 35 providing apassageway having an opening, as at 3S, through the side of the valvefor the egress of air. The recess or chamber 3&5l in the manuallyoperable valve 33 is preferably of larger capacity or sectional area,

. in a plane normal to the direction of air ow toward its outlet 35,increasing in cross-sectional area normal to the direction of air flowso as to provide for expansion of the discharging air. The passageway 35also has a curved wall mrtion 35e for changing the direction of air owso that the member 33V may be made compact and the air be properlydirected. As is more clearly shown in Fig. 3, the manual adjustmentvalve 33 is shown in a position such that substantially only one halfthe area of the discharge opening of the air outlet passageway I4 isuncovered or in communication with the passageway 35 of the valve 33,the other half of `the area of the discharge opening vof the air outletpassageway I4 is uncovered or'in communication with the passageway 35 ofthe valve 33, the other half of the area of the discharge opening I4being covered or closed off by the valve. Inthis positionof the valve 33it will readily be seen that the device isset to vent at one half of therate of its venting capacity. If the valve 33 is pivoted in a clockwisedirection, as seen in Fig. 3, more of the area of the discharge openingof passageway Ill will be uncovered or will communicate with thepassageway 36 through the of venting of air by the device.

Conversely, 1f the valve 33 is rotated in a counterclockwise directionthe area of the discharge opening of passageway I4 communicating withthe passageway 33 of the valve. will be` decreased with correspondingdecreaseV in the venting capacity of the device. A leaf spring or stripof metal 31, and a screw 38 for holding the spring under tension, may beprovided to lock or hold the valve member 33 against movement from adesired position of adjustment. 'The opposite ends of the leaf spring 31may be bifurcatedvv and one end may be positionedl under the head of pin33 and thefother encl may be positioned under the head of the screwA 38.The screw 38 may screw-thread into the upper end of the valve seatmember l and Iis preferably 'disposed so that its headV overlaps theplate-like valve member 33.' The leaf spring 31 is preferably formed orbent. so that when the.- screw 38 is tightened down-the springl wil-l:beplacedunder' tension and will be drawn down against the upper surfaceof the valve member 33.

Preferably the casing I, valve seat member I and adjustment valve 33 areenclosed by a casing 43 which may be of general tubular form, the casing40 preferably being constructed of a heat insulating material. 'Illecasing 40 is pref# erably provided with a slot or aperture 4I throughits top wall, and the manually operable valve 33 is preferably providedwith an operating arm 42 which may project externally of the casing 4I]through the slot 4I. In the present instance, the operating rarm 42 atits outer end, externally of the casing 40, has an upturned portion orhandle 43. The outer casing 4G may be held in place by a single screw 45that may extend into the casing through the side wall thereof and havean inner and preferably pointed end 46 for engaging in a recess in theside wall of the valve seat member I, externally of the inner casing I.Through the top Wall of the outer casing 4B there is provided anaperture 44 through which access may be had from externally of thecasing to the screw 38, with a tool such as a screw driver. The innertop wall surface of the outer casing 40 is spaced from and above thevalve seat member I and cooperates therewith to provide a chamber 41into which air discharges from the passageway of the valve member 33.The chamber 47 is of larger capacity or sectional area, in a planenormal to the direction of iiow of air, than the valve chamber orpassage 35 so that on egress of air from the valve chamber outlet 36,the air will expand in the larger chamber or space 41 with a consequentdecrease in velocity. The inner wall surface of the outer casing IIB isspaced from the outer wallsurface of the inner casing I, and preferablyhas a plurality of spaced, vertically extending ribs 48 and 48a. Betweenthe inner and outer casings, on opposite sides of the rib 48a, there arevertically extending passageways 53 that communicate with the chamber orspace 41 above the valve seat member I0. Preferably the passageways 5I),taken together, have a larger capacity L through the channels orpassageways 50.. Opening through its side wall the outer casing 4U isprovided with an aperture or slot 53 to receive the nipple 5, the slot53 preferably running out of the lower open end of the casing 40. Theslot 53 also provides an opening from the casing 4U for the escape ofair therefrom to outside atmos-I phere, and the area of this opening ismade sufciently large so that there willbe little or no danger of itsbeing painted closed in the event that the outer casing should bepainted to match the radiator. The lower end of the outer casing may beclosed by a plate-like, removable closure member 54. The closure member54 may be held in place by a U-shaped member having a base 55 secured tothe closure member and having upstanding, resilient portions 55 adapteed to position between and. engage the spaced walls of the inner casingI and the cuter casing 40.. As seen in Fig'. 6, 'when the closure member54 is pushedinto place the resilient portions 55 are forced inwardlytoward each other and bowed and placed under tension to therebyfrictionally hold the closure member to the outer casing lll'l.v Also,the resilient holding means acts to hold the inner and outer casingstogether and in proper positions relative to each other.

The operation of my air vent valve is as follows: Valves of thecharacter herein described are particularly suited forheating systemshaving a single supply line with' a commonreturn line, because theventing capacities of the valves may be adjusted in such a manner as toobtain substantially equal and quick distribution of the heating mediumto all of the radiators inthev line. For example, by means of theadjustment valve 33 the rst valve in the line may be set so that only alsmall portion of the area of its venting. port is open, and succeedingvalves may be set to have successively larger venting capacities. As thesteam or other heating medium proceeds through the system to theradiators, it pushes ahead of it the air in the system, causing anincrease in pressure therein. When the valves are set or adjusted sothat their venting capacities vary, increasing in capacity from the rstto the last valve in the line, the resistance of the air to the entranceof steam in succeeding radiators decreases from the first to the lastradiator, which induces steam to flow quickly to all of the radiators.The air flows through the casing I and passes therefrom through thecylinder I2 and passageway I4. From the passageway I4 the air flows intothe passageway or chamber 35 in the adjustment valve 33, where itexpands and whence it takes an abrupt turn and discharges through valvechamber opening or outlet 36 into the chamber or space 4l between thespaced top walls of the inner casing I and the outer casing 40. Theoutlet 36 directs the air away from the apertures 4I and 44 and directlytoward the spaces 53. From the chamber or space 41 the air furtherexpands and flows down through the spaces or passageways 5I) to thebottom of the outer casing 40 where the air escapes to outsideatmosphere through the opening or slot 53. It will be noted that thehead of screw 38 substantially closes the opening 44 and that the airdischarging from valve chamber outlet 36 must be completely reversed inow direction for escape through the partially blocked adjustment opening4I (see Figs. 2 and 3) so that the air which is discharged as shownbythe arrows in Fig. 5 will be required t` turn through only a rightangle for its more free downward discharge. kBy providing for the air toescape into the enclosed chamber 35 of the valve 33, and by providingfor stepped or gradual expansion of the air, as set forth above thehissing noise which formerly occurred in valves of this character isprevented or isginaudible. 'Ihe outer casing 4I) provides a secondaryexpansion chamber for the air to deaden the sound of the escaping air.

position, so long as-the pressure in casing I does not exceed apredetermined pressure. If the pressure in the casing I should increaseto a predetermined pressure, then the valve 21 will be moved upwardthereby into engagement with its seat portion 32h. When the valve member21 is seated, it will be seen that the only path of escape .for the airwill be via the Ismail annular passageway 28 between the inner wallsurface The pressure responsive pistonv valve 21 remains on its seat 32,or inits down of the valve 21 andthe outer wall surface of thethermostatic float valve I1. This will further restrict egress of airfrom the casing I with the result that the accompanying increased airpressure in the casing and radiator will, with greater effect, opposeentrance of the heating medium into the radiator. Thus the pressureresponsive valve 21 acts to provide for substantially equal and quickdistribution of a heating medium throughout a heating system. Onpredetermined decrease in pressure in the system, the valve member 21descends by gravity to its seat on shoulder 32 thereby increasing theventing capacity of the valve. When steam or water enter the casing I,the thermostatic float 2I is respectively heated or buoyed up therebyand moves valve I1 upward against its seat portion 32a to close thepassageway I 4 to flow of the heating medium therethrough and if valvemember 21 is in flow reducing position upon closure of valve I1, thenequalization of pressure as above described causes the valve member 21to open and fall to its seat on shoulder 32. The heat insulating outercasing 40 also prevents rapid dissipation of the heat imparted to theinner metallic casing I by the heating medium, so that if any moisturesuch as that entrained in the vented air gets into the chamber 52between the two casings it will be evaporated. The Water vapor ondischarge from the outer casing 40 will be taken up by the outsideatmosphere and thus dripping of water on the iioor is prevented.

In Fig. 9 there is shown a modiiied form of the valve mem-ber 21 and ofthe cylinder I2 in which modification the upper end wall of casing I andin particular the seat member I has .a downwardly extending hollowcylindrical portion 51 generally similar to the tubular extension t3 ofFig. 2 and providing an inlet passageway 51a of larger diameter than andleading to the port or passageway It as in Fig. 2. The inside diameterof portion is greater than the outside diameter of the valve member I1andV has at its lower end portion a seating surface 58. The upper endportion of valve member I1 extends into the passageway 51*n4 and servesas a guide for a plate-like disk valve member 59 having a centralaperturetherethrough which loosely receives a reduced diameter portionSi) of the valve member I1. of its positions to seat on the valve stemshoulder or seating surface 32 formed at the intersection of the normaldiameter portion. of the member I1 with the portion 6l! and. to havethis position irrespective of whether the. valvemember I1 is closed oropen, and in another position to seat against the seating surface whenvalve member I1 is open. When the velocity` of air owthrough thepassageway' I4 of Fig. 8 exceeds a` predetermined value, then the diskmember 59.y which is suiiciently thin to be light in weight is liftedkinto its position against the surface 58', as shown in dotted lines, tolimit or restrict flow through the passageway I4 so that` the aperturethrough-the disk member 59, which` is sufficiently larger than` theportion 6I), forms an annular now passageway 5I similar to passagewayv28 of Figs. 2 and 1. The spacing of shoulder 32 from shoulder or wall I8permits the valve member I1 to move to closed position when the disk.mem-ber SQ is seated and also. allows disk member 59 to move to openposition` when valve memberjll: is seated. It will be noted that theshoulder or end; wall'. I8 and the annular end` portion` 5E of; the,casing: upper` endlA Walk provide.'

The valve member 59 is adapted in one agentes valve seat. portionsconcentric with passageway i4 and spaced from each other for engagementrespectively by the valve. member I1 and the valve disk or member 59,the valve member I1 engaging the innermost annular seat portion I8 andthe valve member 59 engaging the outermost annular seat portion 58.

From the foregoing description it will now be seen that I have providedanew and improved air vent valve having apressure responsive valvemember which operates on and "oiI in accordance with pressure in thesystem to vary the air venting capacity of, the valve whereby to controlsupply or delivery of a heating medium in the system to the heatexchangers or radiators. I have also provided an air vent valve whichwill vent air Without the usual hissing noise common in such devices.Furthermore, I have provided an air vent valvek of a character such thatthe water entrained by the air is vaporized prior to its escape tooutside-atmosphere. In addition I have provided an air vent valve havingnew and improved adjustment means to regulate the venting capacity ofthe valve.

This application is a continuation in part of my copending VapplicationS. No. 159,554, filed August 17, 1937, for Air vent valves.

What: I claim and desire to securek by Letters Patent of the UnitedStates is:

l. InV an air vent valve` for a heating system, a casing having apassage through a wall thereof including-avalve seat member, athermostatic valve in said casing and extending into said passage,v saidvalve cooperating with said passage to provide an annular chambertherebetween and being operable to engage` said seat member to closesaid passage to ow therethrough, said valve having a. seat' spaced fromand opposed to said seaty member, a pressure responsive open endedtubular valve surrounding said iirst-namedvalve and -arranged to movelongitudinally thereof within said annular chamber and carried bysaidrstnamed valve on said seat, said second-named valve being movablerelative to said rst-named valve. longitudinally of and within saidannular chamber, said. second-named valve on increase in pressure insaid casing engaging said seat member and cooperating with. saidfirst-named valve to. increase the, resistance to flow throughsaidi'passage.

2. In a vent valve, a casing having a valve port with an; outletpassageway leading thereto, said v casing having a seat within saidpassageway and surrounding said port, a rst v-alve member longitudinallymovable in said passageway and controlling: said` port, a1 second valveInez/rber` positioned. in. said passageway andl engageable with said-Lseat: toi control said port, said second valve.

member `being movable. rel ative. to saidI firsty valve member' andihaving an area obstructing ow through said passageway such that saidsecond.

valve'. memberI will be moved to saidl seat Ibya difrerence of uidipressure between the pressure withirrsaid casing and thepressure on theoutlet side of said port.

and surrounding and guided onsaid rst valve member, said apertured valvemember being lifted to.V said; seat by difference. of fluidpressure-betweenY the; pressure withinjsaid. casing'and the y pressureon the outlet side of said port, and means operable to reduce flowthrough said port upon engagement of said apertured valve member withsaid seat, said first valve member being movable through the aperture ofand relative to said apertured valve member to close said port.

4. In a vent valve, a casing having an opening through its top Wall, aplate member closing said opening, said member having a valve port 1 andhaving a cylindrical outlet passageway of enlarged cross-section leadingto said port, said plate member having an annular seat portioninterposed between the Wall of said passageway and the wall of saidport, an automatic valve` member reciprocal in said passageway andoperable to close said port, a pressure responsive valve member withinsaid passageway and surrounding said automatic valve member and spacedfrom the wall of said passageway to deJ termine the venting capacity ofsaid port when said valve members are open, said pressure responsivevalve member moving to said seat portion upon a differential of fluidpressure between the pressure within said casing and the pressure on theoutlet side of said port, means operable upon engagement of saidpressure responsive valve member with said seat portion to reduce therate of ow of uid through said port, a

valve plate overlying said port and pivotally sup-i ported on and forsliding engagement With the top face of said plate member, and meansurging said valve plate into engagement with said plate member, saidvalve plate being operable to require an increased pressure in saidcasing for movement of said responsive valve member to said seatportion.

5. In a vent valve a casing having a top wall with a at outer topsurface and containing a chamber with an outlet port opening upwardlythrough said wall surface, an automatic valve in said chamber andoperable to control flow through said port, a valve plate seating onsaid Wall surface and overlying said port and having a flat surfaceportion engaging said wall surface, said valve plate having a recess inits surface portion with an edge portion movable across said port; tocontrol discharge from said chamber, said recess having an upper Wallmovable into overlying relation to said port and against which the uiddischarging through said port impinges, said valve plate having anopening through its side wall for discharge of fluid from said recess sothat fluid admitted to said recess .from said port is discharged atsubstantially a right angle relative to direction of inow of iiuid tosaid recess, means pivotally supporting said valve plate on said topWall, and resilient means acting on said valve plate to hold saidsurface portion tightly against said topwall surface. l

6. In a vent Valve, a casing having a nat eX- ternal top Wall portionand having an outlet port leading through said portion, a housing memberoverlying and surrounding said casing and having a plurality'ofapertures through its tcp wall, anY automatic valve in 'said casingcontrolling flow through said port, a valve plate within said housingmember and overlying said port and slidably seated on said portion andhaving a portion extending through one of vsaid apertures, meanspivotally securing 4said plate to said casing for swinging movementacross said port to control ow therethrough, resilient means Within saidhousing member holding said valve plate tightly against said wallportion to prevent leakage between said wall portion and said plate andto frictionally oppose movement thereof, said valve plate acting tomaintain substantially constant the restriction to iuid iiow from saidoutlet at a desired value, and means for adjusting the holding effect ofsaid resilient means and positioned adjacent another of said aperturesfor operation externally of said housing member, said adjusting meansbeing operable to lock said valve plate against movement by saidextending portion.

'7. In an air vent valve, a casing having an outlet port with a'seatingsurface, an adjustable valve member cooperable with said surface to forma valve means for controlling owthrough said port, and means providingan elongated air flow passageway leading from the outlet side of saidvalve means and operable to conduct air from said valve means, saidpassageway having an outlet of larger flow area than said valve meansand having a streamline contour of progressively increasingcross-sectional flow area to its outlet so that the air dischargingthrough said valve means will have a progressively gradually decreasingvelocity prior to discharge from said passageway thereby to reduce thenoise of air discharging from said valve means.

8. In a vent valve, a casing having a chamber with an outlet port at itsupper end portion, an automatic valve in said chamber and controllingsaid port, a housing overlying and surrounding said casing and having anupper end wall spaced from said casing, said housing having anvopeningthrough said end wall, a manually operable valve pivotally mounted toswing across said port to control flow through said port and operable tomaintain a desired substantially constant restriction to fluid flow, aclamping spring operable to hold said manually operable valve inadjusted position, means to adjust the tension of said spring andoperable to prevent movement of said manually operable valve, saidhousing having an aperture therethrough for access to said adjustingmeans, and an operating member rigid with said manually operable valveand positioned between said casing and said end wall and having a fingergrip portion projecting through said end Wall opening.

9. In a vent valve for a steam system, a casing having a chamber forVcommunication with the system and to lbe heated by steam admitted fromthe system, said chamber having an outlet port at its upper end portion,an automatic valve in said chamber andb controlling said. port to allowair to flow through said port thereby to vent the system, a housingoverlying and surroundingsaid casing and lhaving an imperforateside Walland having an outlet atfits lower end portion and having an opening`through its upper end portion, said housing and said casing cooperatingto forman annular passageway, an adkjustable valvemember carried by saidcasing and determining theeifective flow area of said port andadjustablefrom externally of said-housing through said upper opening,and means to bdirect air-entrained liquid discharging from said portinto said annular passageway so that the' discharging liquid will passoverfand be confined closely relative to saidvk casing so as to bevaporized prior to discharge through said lower housing outlet. v

l0. In a vent valve for a steam system, a casing having a chamber forcommunication with the system and to be heated by steam admittedj-portaat iits .uppergend portion, .an automatic valve ainfsaid chambervand: controlling said port to al- *lowthefpassage of yairvthrough saidport thereby -to-` vent vthe system, 4said-.valve being' adapted toprevent'thefow of'steam` through said port, a -housing overlying andsurrounding. said casing and having an `imperiorate side -Wall andan.aperturedtop wal1,a manually yoperable valve .rmeanscooperable withsaid-port and having a Vn'lovableportion extending, through Saidtop'wall aperture, and means for discharging adjacent :thewbottom wallof said housingfluidy passing .throughsaid port, said steam heatedrcasingacting to yvaporize :any Ientrained water in the nvente'd'airprior to discharge thereof through said discharging means.

1l. Ina vent valve,a casing having a chamber -with an outlet port at itsupper end portion,

-said'casing having -aninlet nipple extending -frorn its side walladjacent its lower end porsaid casing having in its side wall adjacentits lower end a slot through Whichsaid nipple extends and meanslorsecuring said housing to said casing solely at said chamber `upperend portion.

12. An air vent valve comprising a casing having a port in its top wallwith a downwardly directed open-ended. passageway on the .inletsideofaandleading to said port,- a oat member in said' casing, anupwardlysextending stem on said float member, a vvalve on said stemoperable to 'directly-engage said .casing to'close said port, a valvemember movable into cooperable relation .with the wall of said casing onthe inlet side of said port thereby to reduce ilow through said port,said valve member being apertured to receive said stem so that saidvalve member is reciprocallyguided byV said stem, and a shoulder on saidstem supporting said valve member in a position relative to saidpassageway such that air flow will lift said valve member .into saidcooperable relation when said valve is open thereby to reduce air owthrough said port, said valve acting upon engagementwith said casing'tocause an equalization of pressures acting on said valve member therebyto cause said valve member to move into engagement with said shoulderand out of said cooperable` relation.

13. An air vent valve comprising a casing having a'port in its top walland a vdownwardly eX- tending tubular-member definingy a,A passagewayleading to said'port, said tubular member having a lower end wall whichforms a seating portion, a float memberl in said casing, an upwardlyextending stem on said oat member, a valve on said stem operable toclose said port, a thin platelike disk member engageable with saidseating portion to reduce iiow through said port,said disk member beingapertured to receive said stem so that said disk member is reciprocallyguided .by said stem, and a shoulder on said stem supporting said valvemember in a position relative to said passageway such that airiiow willlitt said disk member into engagement with said seating ,fromzthesystem, said chambcrhaving-xanoutlet v portion-when saidvalvev-isopenthereby. to, reduce air flow through said port.

14. An airvent-.valve comprisinga casing having a vent port at its upperend, a. housing having .a top wall and an imperforate side Wall andoverlying and surrounding said casing, meansl securing said housingsolely at its upper endto the .upperend of said casing, said housingvprothe noise ofair dischargingI from saidrport, and -an automaticvalvezin saidcasingcontrolling said port.

15. y An ain vent` valve comprising a casing having a vent at it s1:lp1fer .end,.=a` housing having a top wall and an imperforate side wall andoverlying and surrounding said casing, said housing being supported atits vupper end on the upper end ofsaid casing and providing around saidcasing a downward :discharging passageway lead- .ing from said port, anautomatic valve in said casing engageable with the wall of said casingand controlling ow through said port, a pressure responsive valvecarried' by said automatic valve and controlling the inlet to saidport,a manually 'operable Valve controlling the outlet from said port, saidhousing having an opening in its top wall adjacent said manual valve,and means exytending `into said ,opening for vadjusting said manualvalve to require an increased pressure in said casingfor movement ofsaid responsive valve VVsagewav, an inlet nipple projecting from thecasingside wall'adjacent its lower end, and a housing having'a topwall'and an imperforate side wallapertured to receive said nipple, saidhousing beingsecured to and hanging from said seat vmember and providingaround said casing a downward discharging passageway.

17. An airvent valve comprising a casing ccntaining a chamberl and`having a top wall with a passageway therethrough leading -from saidchamber said wall having seat portions sub- .'-stantially concentricwith said passageway and -spacedffrom each-other,;a oat member in saidcasing,-an upwardly extending stem on said oat member, a valve onlsaidstem operable to engage the innermost one lofsaid-seatfportions to'closesaid passageway, va valve member cooperable withsaid top wall andengageable with the out- -ermost one of said seat :portions toreduceflow through said passagevvavfsaid valveimernber being -apertured.to receive 4and to `be reciprocally lguided on said 'stem,'and ashoulder on said stem supportingsaid `valve vmember in apositionrelative to said passageway such that when said oat member valve.is open, air'flow'will lift said valve member toward said outermostoneiof said

